Re: [Patch] PR56064: Fold VIEW_CONVERT_EXPR with FIXED_CST, Take #2

[Richard Biener <richard.guenther@gmail.com>]

On Tue, Jan 29, 2013 at 9:00 PM, Georg-Johann Lay <avr@gjlay.de> wrote:
> Richard Biener wrote:
>> Georg-Johann Lay wrote:
>>> This is tentative patch as discussed in
>>>
>>> http://gcc.gnu.org/ml/gcc/2013-01/msg00187.html
>>>
>>> fold-const.c gets 2 new function native_encode_fixed and
>>> native_interpret_fixed.  Code common with the integer case is factored out and
>>> moved to the new constructor-like function double_int::from_buffer.
>>>
>>> The code bootstraps fine on x86-linux-gnu and I have test coverage from
>>> avr-unknown-none.
>>>
>>> Ok to apply?
>>
>> Ok.
>>
>> Thanks,
>> Richard.
>
> Let me drop this, I don't like the name "const_fixed_from_double_int".  It's
> bad and I think "fixed_from_double_int" is better.  Other constructor-like
> functions for FIXED_VALUE_TYPE use fixed_from_* whereas const_fixed_* returns a
> CONST_FIXED rtx.
>
> This is less confusing and fits better the naming convention.
>
> The new patch also adds const_fixed_from_double_int that actually returns a
> CONST_FIXED rtx.  It's unused, but I would use it in the avr back.
>
> Okay with that rename? (Or, at your option, without const_fixed_from_double_int).

Ok.

Thanks,
Richard.

> Johann
>
>
>         PR tree-optimization/56064
>         * fixed-value.c (fixed_from_double_int): New function.
>         * fixed-value.h (fixed_from_double_int): New prototype.
>         (const_fixed_from_double_int): New static inline function.
>         * fold-const.c (native_interpret_fixed): New static function.
>         (native_interpret_expr) <FIXED_POINT_TYPE>: Use it.
>         (can_native_interpret_type_p) <FIXED_POINT_TYPE>: Return true.
>         (native_encode_fixed): New static function.
>         (native_encode_expr) <FIXED_CST>: Use it.
>         (native_interpret_int): Move double_int worker code to...
>         * double-int.c (double_int::from_buffer): ...this new static method.
>         * double-int.h (double_int::from_buffer): Prototype it.
>
> testsuite/
>         PR tree-optimization/56064
>         * gcc.dg/fixed-point/view-convert.c: New test.
>
>
>
>>
>>> There are less intrusive solutions that only handle the int <-> fixed cases,
>>> for example fold-const.c:fold_view_convert_expr() could test for these cases
>>> and use double_int directly without serializing / deserializing through a
>>> memory buffer.
>>>
>>> Johann
>>>
>>>
>>>         PR tree-optimization/56064
>>>         * fixed-value.c (const_fixed_from_double_int): New function.
>>>         * fixed-value.h (const_fixed_from_double_int): New prototype.
>>>         * fold-const.c (native_interpret_fixed): New static function.
>>>         (native_interpret_expr) <FIXED_POINT_TYPE>: Use it.
>>>         (can_native_interpret_type_p) <FIXED_POINT_TYPE>: Return true.
>>>         (native_encode_fixed): New static function.
>>>         (native_encode_expr) <FIXED_CST>: Use it.
>>>         (native_interpret_int): Move double_int worker code to...
>>>         * double-int.c (double_int::from_buffer): ...this new static method.
>>>         * double-int.h (double_int::from_buffer): Prototype it.
>>>
>>> testsuite/
>>>         PR tree-optimization/56064
>>>         * gcc.dg/fixed-point/view-convert.c: New test.
>>
>